This invention relates to communication systems, including but not limited to identifying access technologies in wireless communication systems.
Various types of cellular communication systems are known to provide radio telephone service to a large number of mobile subscribers using a relatively small number of frequencies. Such service is provided by dividing a service area into a number of cells and reusing the frequencies in non-adjacent cells. This cellular principle has permitted a large growth in the amount of wireless telecommunications that may be carried over the allocated radio spectrum thus providing significant expansion in the number of wireless communication subscribers.
Cellular systems utilize many different technologies for communication access. The oldest type of cellular system is an analog system. Another cellular system is a digital system that is based upon time division multiple access (TDMA) techniques, such as that defined in Telecommunications Industry Association Interim Standard (TIA) IS-136. Yet another cellular system employs code division multiple access (CDMA) techniques and is defined in TIA IS-95. Still another cellular system combines TDMA and frequency division multiple access (FDMA) techniques and is known as the Global System for Mobile Communications (GSM), that was developed by Groupe Special Mobile of the European Conference of Posts and Telecommunications (CEPT) and its successor, the European Telecommunications Standard Institute (ETSI).
When a mobile roams in a system that is not its home system, the mobile may access any technology that the system provides and with which the mobile is capable of communicating. When call activity for the mobile is routed to the home system, it may not know which technology the mobile is presently using to access a visited system, and the visited system may flood all technologies in the system with pages to find the mobile. Such a process is a very inefficient use of resources and may cause congestion on the forward control channels for the various systems.
Accordingly, there is a need for a method to find a mobile in a multiple-technology environment without wasting bandwidth on the forward control channels for each technology.
A visited system receives a registration request to access the visited system via an access technology for a mobile unit that is associated with a home system having a home location register. A registration notification, including an identification of the access technology, is forwarded to the home location register.